We examined the compensation effect of by-product – so called “digestate” –which is originated from Biharnagybajom, in the case of nutrient deficiency. The experimental plant was sunflower (Helianthus annuus L. cv. Alego) is grown under laboratory conditions.

Previously we observed that the digestate contains several essential elements for plants. The dry weight of shoots and roots, the relative chlorophyll content of the 1st and 2nd leaves (SPAD unit), the photosynthetic pigments (chlorophyll-a, chlorophyll-b, carotenoids) and the up-taken elements (Ca, Mg, P and K) were measured during the experiment. Based on the results of the performed experiments, it was concluded that digestate had positive effect on dry weight of shoots and roots of sunflower. The dry weight of the sunflower shoots was 0.7–1.4 g plant-1 (potassium deficiency, potassium deficiency+digestate), the dry weight of the sunflower roots was 0.005–0.21 g plant-1 (calcium deficiency, potassium deficiency+digestate).

The relative chlorophyll content (SPAD-unit) was increased by the digestate treatments compared to nutrient deficient treatments. The highest relative chlorophyll value was measured at potassium deficiency+digestate treatment, this value was 43.22 SPADunits in the first leaf and 41.39 SPAD-units in the second leaf. When the digestate was added to the nutrient-deficient nutrient solution, more favorable effects were achieved on the measured parameters like photosynthetic pigments and the elements uptake.

Due to these results, we suggest the use of digestate in agriculture production, especially on element-deficient soil conditions or when the uptake of macro- and mesoelements is blocked.

Keywords: crop production, digestate, nutrient deficiency, nutrient supply, sunflower